Evaluating Lead Halide Perovskite Nanocrystals as a Spin Laser Gain Medium

Abstract

Spin-polarized charge endows conventional lasers with not only new functionalities but also reduced lasing thresholds thanks to the lifting of spin degeneracy. II−VI and III−V semiconductors have been extensively investigated as spin laser gain mediums; however, the degree of polarization is limited by the light hole and heavy hole degeneracy. Herein, we evaluate the potential of CsPbBr 3 nanocrystalsones that are featured with low band-edge degeneracy and therefore a high degree of polarization as a result of inverted band structure and large spin−orbit couplingas a gain medium for spin lasers. Our experiment and numerical modeling results reveal that, within the spin relaxation lifetime, the optical gain threshold can be depressed by polarizing the charge using circularly polarized photoexcitation. However, prolonging the spin relaxation lifetime is required to realize a spin laser.

Dopant-Induced Slow Spin Relaxation in CsPbBr3 Perovskite Nanocrystals

“…In a spintronic device, information is recorded in the spin-polarized state of electrons or holes, and the intrinsic spin-relaxation time (longitudinal spin-flip time, T 1 ) thus plays an important role in determining the device performance. − A longer spin-relaxation time is usually an essential prerequisite for practical use in spintronic devices. However, the strong SOC effect in LHPs, on the other side, can also reduce the spin-relaxation time (usually down to a few ps), which in turn limits their spin-related applications.…”

Recent progress and future prospects on halide perovskite nanocrystals for optoelectronics and beyond

“…For the case of CsPbBr 3 NCs, it was found that the optical gain threshold could be depressed by polarizing the charge using circularly polarized photoexcitation. Nevertheless, the spin relaxation time was too short to realize a spin laser ( Tang et al., 2022 ). If the spin relaxation time could be prolonged, the threshold reduction would be more remarkable under quasi-continuous wave photoexcitations.…”

Up‐Converted Long Persistent Luminescence from CsPbBr3 Nanocrystals in Glass

“…All‐inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, I) perovskite materials have recently evoked considerable attention in the fields of solar cells, [ 1 ] laser, [ 2 ] and photodetectors, [ 3 ] owing to their outstanding optoelectronic performance, such as large absorption coefficient, high photoluminescence quantum yield (PLQY), narrow emission band, and tunable bandgap. These superior features make CsPbX 3 perovskites ideal candidates as light‐harvesting and light‐emitting materials for a variety of optoelectronic [ 4 ] and photovoltaic [ 5 ] applications.…”